Method of molding a shoulder on a vertical mandrel



July 19, 1966 3,261,901

GEORG KOPP ALSO KNOWN As JORG KOPP METHOD OF MOLDING A SHOULDER ON AVERTICAL MANDREL Filed April 1, 1963 4 Sheets-Sheet 1 July 19, 19663,261,901 GEORG KOPP ALSO KNOWN As JORG KO Filed April 1 1963 METHOD OFMOLDING A SHOULDER ON A VERTICAL MANDREL 4 Sheets-Shee t 2 July 19, 19663,261,901

GEORG KOPP ALSO KNOWN AS JQRG KOPP METHOD OF MOLDING A SHOULDER ON AVERTICAL MANDREL 4 Sheets-Sheet 5 Filed April 1, 1963 July 19, 19663,261,901

GEORG KOPP ALSO KNOWN AS JQRG KOPP METHOD OF MOLDING A SHOULDER ON AVERTICAL MANDREL 4 Sheets-Sheet 4 Filed April 1, 1963 United StatesPatent 3,261,901 METHOD OF MOLDING A SHOULDER ON A VERTICAL MANDRELGeorg Kopp, also known as Jiirg Kopp, Schatfhausen,

Switzerland, assignor to Schweizerische Industrie- Gesellschaft,Neuhausen am Rheinfall, Switzerland Filed Apr. 1, 1963, Ser. No. 269,676Claims priority, application Switzerland, Apr. 3, 1962, 4,039/62 9Claims. (Cl. 264219) The present invention relates to formers for use inmaking tubes from strip material, such as cardboard, supplied from aroll.

Packaging machinery is often constructed wherein a packing tube isformed from a strip of material running off a roll, and this tube isthen filled and processed into individual packages. For this purpose,the strip of material is folded round a mandrel, a former or socalledforming shoulder guiding the strip through an angle greater than 270onto the mandrel. Such a forming shoulder has an interior concavecylindrical surface extending through it from one end to an oppositeend, such cylindrical surface being of slightly larger diameter than themandrel. One edge of the cylindrical surface forms a folding edgecurving smoothly from each side of a central portion thereof at the rearof the forming shoulder to the front of the shoulder and towards theopposite edge of the cylindrical surface. A flat exterior rear surfaceof the shoulder is inclined at an acute angle to the axis of thecylindrical surface and extends to said central rear portion of thefolding edge whilst convex exterior curvilinear side surfaces blend withthe flat rear surface and extend therefrom forwardly to the remainingportions of the folding edge. The strip material is fed along the fiatsurface and over the curvilinear surfaces to the folding edge. At thefolding edge the material is bent through a sharp angle (over 270) andpasses as a tube through the annular clearance space between theinternal cylindrical surface and the mandrel which extends through thebore formed by this cylindrical surface.

These forming shoulders have hitherto been hand made of metal by skilledcraftsmen. This is very time consuming and therefore expensive andfurthermore is subject to inaccuracies which may prevent the strip ofmaterial running smoothly over the forming shoulder.

The invention concerns a forming shoulder for the above stated purposeand a process by means of which these forming shoulders may be producedmore quickly, more cheaply and above all more accurately than hashitherto been possible.

According to one aspect of the present invention, a method of making aforming shoulder includes the steps of arranging a cylindrical mandrelwith its axis generally vertical; folding a foil in strip form about thecylindrical mandrel so that one end part of said foil is in tubular formabout said mandrel, the other end portion of the foil is flat andinclined downwardly to the axis of the mandrel at the same angle as thestrip material to be formed into a tube will be fed and the foil takesthe general shape which will be assumed by the strip material beingfolded, a mould cavity thereby being formed about the foil portion inthe form of a tube; casting a settable composition into said mouldcavity to form a cast body; and removing said foil from said cast bodyto provide a forming shoulder.

Preferably the mandrel is enclosed by a sleeve which is covered withadhesive on the outside and the adhesive sleeve is covered by thetubular portion of the foil. Said composition cast into the mould cavityis preferably one which solidifies practically without shrinkage.

According to another aspect of the invention, a forming shoulder forforming strip material into a tube about a cylindrical mandrel has aninterior concave cylindrical 3,261,901 Patented July 19, 1966 surface ina hole extending through said shoulder, one edge of said cylindricalsurface being radiused to provide a folding edge which curves smoothlyupwardly from each side of a central portion thereof at the rear of saidshoulder to the front of said shoulder, a flat exterior rear surfaceinclined at an acute angle to the axis of said cylindrical surface andextending towards said central rear portion of said folding edge, convexexterior curvilinear side surfaces blending with said flat rear surfaceand extending therefrom towards said folding edge and an exterior bordersurface adjoining said radiused folding edge, said border surfaceblending with said curvilinear side surfaces and with said flat rearsurface, and being slightly curved concave to said folding edge.

The method of producing the forming shoulder and the shoulder itselfwill be further described by way of example with reference to theaccompanying drawings wherein:

FIG. 1 is a side view of a folding mandrel around which is arranged aflexible foil which is folded to the form of a strip of material whichis to be folded into a tube as it is being guided over the formingshoulder.

FIG. 2 is a front perspective view of the mandrel and the foil, thecavity in the foil having been filled with a settable composition;

FIG. 3 is a plan view corresponding to FIG. 2.

FIG. 4 is a front perspective view of the forming shoulder which hasbeen cast in the cavity.

FIG. 5 is a rear perspective view of the shoulder;

FIG. 6 is section to a larger scale through the folding edge of theforming shoulder on the line VIVI in FIG. 4;

FIG. 7 is a plan view similar to FIG. 2, but of another embodimentbefore the cavity is filled;

FIG. 8 shows an aluminum foil provided with transverse ridges; and

FIG. 9 is a rear perspective view of a shoulder cast in a cavity formedby the ribbed foil of FIG. 8;

Referring to the drawings and more particularly to FIGS. 1 to 4, amandrel 1, which is either the mandrel used in a packaging machineitself or a mandrel of the same diameter, is enclosed by a cardboardsleeve 2 which is covered with adhesive on the outside. If the packagingtube which is to be produced by means of the forming shoulder to be madeis to have an overlapping longitudinal seam, then the longitudinal edges10, 11 of the cardboard sleeve will also be made to overlap, as shown inFIGS. 2 and 3.

A piece of flexible foil 3 having a very smooth surface, for example, analuminum foil, is now secured to the adhesive outer surface of thecardboard sleeve 2 in such a manner that one end portion 15 of the foilis correctly formed into a tube. The foil 3 is preferably cut to thesame width as the cardboard of the sleeve 2 so that when its end portion15 is wound round the sleeve, its longitudinal edges 16, 17 will beflush with the overlapping longitudinal edges 10, 11 of the sleeve 2.

The lower end of the tubular or cylindrical portion 15 terminates a told19 which extends smoothly upwardly from a central rear portion 19a tothe lateral edges 16 and 17.

The other end portion 18 of the foil 3, forms a flat rear portion atangle a to the axis of the mandrel 1, when the foil 3 is curved roundthe mandrel and extends downwardly inwardly towards the central rearfold portion 19a.

Curvilinear side portions 20 and 21 of the foil 3 blends with the fiatrear portion 18 and extends forwardly and downwardly towards the bend19. A cavity 4 is formed around the mandrel 1 and the sleeve 2 and sincethe foil 3 takes the shape of thestripof packaging material running intothe packaging machine when it is being folded into a tube, this cavity 4formed by the foil 3 can be used as a mould cavity, for casting aforming shoulder.

A border file portion 22 (FIG. 6) adjoining the blend 19 blends with thecurvilinear portions 20 and 21 and with the lowermost part 180 of thefiat foil portion 18. The border portion is curved slightly concavedownwardly towards the bend 19 with a radius R The bend 19 itself is notabsolutely sharp but has a radius R The radii R and R depend on thethickness of the aluminum foil, which may be about 0.08 to 0.10 mm.These radii of curvature vary over the whole length of the bend 19 andare determined by the balancing of the internal stresses in the foil 3,so that a practical ideal casting cavity is obtained.

The cavity 4 is now filled with a settable composition which solidifieswithout any marked shrinkage. Synthetic materials are preferably usedfor this purpose; for example acrylates, nylon and epoxy resins havebeen found satisfactory. The casting process may be carried out eitherby simply filling the cavity 4 up to its edge with liquid syntheticresin 5, as shown in FIGS. 2 and 3, in which case it may be advantageousto add filler to the synthetic resin, or the synthetic resin may beapplied in layers or sprayed in or applied by some other suitableprocess.

When the synthetic resins 5 has solidified, th foil 3 and the sleeve 2are removed to provide a forming shoulder 25. FIGS. 4 and 5 show aforming shoulder 25 produced as described above. This shoulder has aninternal concave cylindrical surface 26, a fiat rear surface 27 inclinedto the axis of the cylindrical surface 26 at the angle on andcurvilinear side surfaces 28 and 29 produced by the correspondingportions 15, 18, 20 and 21 of the foil 3. The curvilinear side surfaces20 and 21 blend with the rear surface 18 and extend forwardly anddownwardly towards a folding edge 30 forming the lower edge of thecylindrical surface 26. The fiat rear surface 27 extends downwardlyinwardly towards the folding edge 30. As shown in FIG. 6, which shows adetail of the forming shoulder before the removal of the foil, thisshoulder has a border surface 31 adjoining the folding edge and blendingwith the curvilinear side portions 28 and 29 and with the lowermost part27a of the flat portion 27. This border surface 31 is slightly concavedownwardly towards the edge 30 with the radius R of the correspondingborder portion 22 of the foil. Likewise the edge 30 itself has theradius R of the corresponding bend 19 of the foil. As the cast formingshoulder has all the details of the cavity 4, the folding edge 30considerably improves the guiding of the oncoming strip of packagingmaterial compared with that achieved with the prior art formingshoulders, so that even packaging materials of extremely lowstretchability, e.g. backed aluminum foils, can be worked by the formingshoulder perfectly satisfactorily and without any subsequent work on theforming shoulder.

The forming shoulder may either be fixed directly to the folding mandrelof the packaging machine or it may be used as a pattern for producingmoulds from which any number of forming shoulders may be produced.

If desired, the foil 3 may be suitably treated, e.g. it may bereinforced from outside by means of synthetic resins or metals, so thatit may itself be used as a master mould for the production of any numberof forming shoulders.

The thickness of the cardboard used for the sleeve 2 may be selectedaccording to the thickness of the strip of packaging material to befolded. If necessary, the mandrel 1 used for the production of theforming shoulder may have a slightly greater diameter than the mandrelused in the packing machine. Furthermore, the angle 0: may be adjustedto the thickness and type of packaging material. It is usually about 30to In cases wherein the packaging tube produced by the shoulder is tohave a longitudinal seam which projects radially from the tube thelongitudinal edges 12, 13 of A the cardboard sleeve 14 are arranged toproject radially from the mandrel 1 as shown in FIG. 7. In this casealso the longitudinal edges 32, 33 of the tubular portion 34 of the foil35 are in register with the cardboard edges 12, 13. The foil shape ofFIG. 7 is otherwise the same as that of FIGS. 1. to 3.

If a foil 36 provided with ridges 37 as shown in FIG. 8 is folded aboutthe mandrel, the forming shoulder 38 produced by casting in the cavityformed by folding the foil about a mandrel as in FIGS. 1 to 3 will havecorresponding ribs 39 which may, for example, run transversely to thedirection in which the strip of packaging material is to move forward asshown in FIG. 9. Only the portion 40 of the foil 36 which is to be madetubular is free from ridges 39. Both that portion 41 which will remainflat and those portions 42 and 43 which are to become curvilinear areridged. On the one hand, these ribs 39 considerably reduce the surfaceof contact and hence the frictional resistance of the strip and on theother hand, for example in the case of polyethylene, it reduces theelectrostatic charge.

For the purpose of fixing the finished forming shoulder easily to amachine in accordance with its purpose the necessary mounting orsecuring members may advantageously be cast directly into the shoulder.

I claim:

1. In a method of shaping and molding a forming shoulder for formingstrip material into a tube about a cylindrical mandrel: the steps ofapplying a cylindrical adhesive sleeve to said mandrel to form a supportwith its axis generally vertical; folding a flexible foil in strip formabout the sleeve, bending said foil upwardly from its lower edge intothe shape which will be assumed by the strip material being folded toform a mold wall offset from said mandrel axis, such shape including atubular mold wall portion about said mandrel formed with a bend at thelower end of said tubular portion and formed by bending the foilupwardly, and a fiat rear portion inclined upwardly from said bend at anacute angle to the mandrel axis towards said bend, said molds forming amould cavity between said folded foil and said tubular foil portion;casting a settable composition into said mould cavity to form a castbody; permitting setting of said composition and removing said foil fromsaid cast body to provide a forming shoulder.

2. The method according to claim 1 wherein said foil is aluminium foil.

3. In a method of shaping and molding a forming shoulder for formingstrip material into a tube about a cylindrical mandrel: the steps ofapplying a cylindrical sleeve with its axis generally vertical; foldinga flexible foil in strip form about said sleeve, bending said foilupwardly to form inner and outer mold walls and into the shape whichwill be assumed by the strip material being folded, such shape includinga tubular portion about said mandrel forming said inner wall, theupwardly bending of the lower portion of said foil forming a bend at thelower end of said tubular portion, with a flat rear wall portioninclined upwardly from said bend at an acute angle to the mandrel axisaway from said bend, said walls forming a mould cavity between saidupwardly folded foil and said tubular foil portion; casting a settablecomposition into said mould cavity to form a cast body, said compositionhaving the property that it is substantially non-shrinking uponsolidification; and removing said foil from said cast body to provide aforming shoulder.

4. In a method of shaping and molding a forming shoulder for formingstrip material into a tube about a cylindrical mandrel; the steps ofpositioning a cylindrical mandrel with its axis generally vertical;applying a sleeve to said mandrel; adhesively securing a strip of foilmaterial to a portion of said sleeve, folding said foil in strip formabout said sleeve, bending said foil upwardly from its lower end to formmold walls and of a shape after the strip material is folded, such shapeincluding a tubular portion, a bend at the lower end of said tubularportion and a flat rear portion inclined upwardly from said bend at anacute angle to the mandrel axis, the bending of said foil forming amould cavity in said folded foil about said tubular foil portion;casting a settable composition into said mould cavity to form a castbody; permitting said composition to set, and removing said foil fromsaid cast body to provide a forming shoulder.

5. The method according to claim 4 wherein said sleeve is comprised ofcardboard with a layer of adhesive on the outside thereof.

6. In a method of shaping and molding a forming shoulder for formingstrip material into a tube about a cylindrical mandrel: the steps ofarranging a cylindrical mandrel with its axis generally vertical;wrapping a foil in strip form about the cylindrical mandrel, folding thelower portion of said foil upwardly to form a cylindrical portionwrapped around said mandrel and an offset wall portion spaced therefrom,said cylindrical portion having a front longitudinal seam formed byjuxtaposed lateral edge portions of the foil, bending the lower end ofsaid cylindrical portion upwardly to form a mould cavity, said bendcurving smoothly forwardly upwardly from each side of a central rearportion thereof to the lower end of said seam, a flat rear portioninclined at an acute angle to the mandrel axis downwardly towards saidcentral rear portion of said bend and convex curvilinear portionsblending with said fiat rear portion and extending therefrom forwardlyand downwardly to said bend, a mould cavity thereby being formedexteriorly of said cylindrical foil portion but interiorly of said fiatrear and curvilinear side foil portions; filling a settable compositioninto said mould cavity, permitting setting in said mould cavity of saidcomposition substantially without shrinkage to form a cast body; andfinally removing said foil from said cast body to provide on said bodythe shape of a forming shoulder.

7. The method according to claim 6 wherein said foil, before it isdeformed, is ridged at least over those regions which become said flatand curvilinear side portions, ribs thereby being formed over thecorresponding surfaces of said cast body.

8. In a method of shaping and molding a forming shoulder for formingstrip material into a tube about a cylindrical mandrel: the steps ofarranging a cylindrical mandrel with its axis generally vertical;wrapping a foil in strip form about the cylindrical mandrel, folding thelower portion of said foil upwardly to form a cylindrical portionwrapped around said mandrel and an eccentric curved portion, saidcylindrical portion having a front longitudinal seam formed byjuxtaposed lateral edge portions of the foil, said folding step forminga radiused bend at the lower end of said cylindrical portion with saidbend curving smoothly forwardly upwardly from each side of a centralrear portion thereof to the lower end of said seam, said bending andfolding step also forming a Hat rear portion inclined at an acute angleto the mandrel axis downwardly towards said central rear portion of saidbend with convex curvilinear portions blending with said flat rearportion and extending therefrom forwardly and downwardly towards saidbend and a border portion adjoining said bend, said foil being bent sothat the same will form a border portion blending with said curvilinearside portions and being slightly curved concave downwardly to said bend,a mould cavity thereby being formed exteriorly of said cylindrical foilportion but interiorly of said fiat rear, curvilinear side and borderfoil portions; filling a settable composition into said mould cavity,permitting said composition to set in said mould cavity substantiallywithout shrinkage to form a cast body; and removing said foil from saidcast body to provide on said body the shape of a forming shoulder.

9. In a method of shaping and molding a forming shoulder for formingstrip material into a tube about a cylindrical mandrel: the steps ofpositioning a cylindrical mandrel with its axis generally vertical;applying a foil in strip form about the cylindrical mandrel, folding andbending said foil upwardly from its lower edge to form a cylindricalmold wall portion wrapped around said mandrel and an eccentric mold wallportion, said cylindrical portion having a front longitudinal seamformed by juxtaposed lateral edge portions of the foil, said foldingstep forming a bend at the lower end of said cylindrical portion curvingsmoothly forwardly upwardly from each side of a central rear portionthereof to the lower end of said seam with a flat rear portion inclinedupwardly at an acute angle to the mandrel axis and downwardly towardssaid central rear portion of said bend with a convex curvilinear surfaceblending with said flat rear portion and extending therefrom forwardlyand downwardly towards said bend and a border portion said bend andblending with said curvilinear side portions, said bend being radiusedand said border portion being slightly curved concave downwardly to saidbend in accordance with the thickness of the foil and said acute angle,a mould cavity, said folded and bent foil forming between saidcylindrical foil portion and said outwardly and upwardly extending andfolded curvilinear side and concave border foil por tions; filling asettable composition into said mould cavity, permitting setting of saidcomposition in said mould cavity to form a cast body; and removing saidfoil from said cast body to provide on said body the shape of a formingshoulder after said composition has set.

References Cited by the Examiner UNITED STATES PATENTS 2,662,248 12/1953Ames 264-219 2,708,773 5/1955 Bacon 264-219 2,810,935 10/1957Gaydebouroff 264-219 3,122,072 2/1964 Monsees et al. 93-82 3,125,0083/1964 Herdina 93-82 ROBERT F. WHITE, Primary Examiner. BERNARDSTICKNEY, Examiner. R. B. MOFFITI, Assistant Examiner.

1. IN A METHOD OF SHAPING AND MOLDING A FORMING SHOULDER FOR FORMINGSTRIP MATERIAL INTO A TUBE ABOUT A CYLINDRICAL MANDREL: THE STEPS OFAPPLYING A CYLINDRICAL ADHESIVE SLEEVE TO SAID MANDREL TO FORM A SUPPORTWITH ITS AXIS GENERALLY VERTICAL; FOLDING A FLEXIBLE FOIL IN STRIP FORMABOUT THE SLEEVE, BENDING SAID FOIL UPWARDLY FROM ITS LOWER EDGE INTOTHE SHAPE WHICH WILL BE ASSUMED BY THE STRIP MATERIAL BEING FOLDED TOFORM A MOLD WALL OFFSET FROM SAID MANDREL AXIS, SUCH SHAPE INCLUDING ATUBULAR MOLD WALL PORTION ABOUT SAID MANDREL FORMED WITH A BEND AT THELOWER END OF SAID TUBULAR PORTION AND FORMED BY BENDING THE FOILUPWARDLY, AND A FLAT REAR PORTION INCLINED UPWARDLY FROM SAID BEND AT ANACUTE ANGLE TO THE MANDREL AXIS TOWARDS SAID BEND, SAID MOLDS FORMING AMOULD CAVITY BETWEEN SAID FOLDED FOIL AND SAID TUBULAR FOIL PORTION;CASTING A SETTABLE COMPOSITION INTO SAID MOLD CAVITY TO FORM A CASTBODY; PERMITTING SETTING OF SAID COMPOSITION ANS REMOVING SAID FOIL FROMSAID CAST BODY TO PROVIDE A FORMING SHOULDER.